[Android 5.15] KASAN: slab-out-of-bounds Write in firmware_param_path_get

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 61d896ee2a80 Revert "hdlc_ppp: sync per-proto timers befor..
git tree: android13-5.15-lts
console+strace: https://syzkaller.appspot.com/x/log.txt?x=15d6649e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=43676e801f1929a9
dashboard link: https://syzkaller.appspot.com/bug?extid=ce44dea18b8e29d68ded
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=131717b1580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15c14aea580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bcb85cf50754/disk-61d896ee.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7e4ac22ab0e5/vmlinux-61d896ee.xz
kernel image: https://storage.googleapis.com/syzbot-assets/14b47a248e31/bzImage-61d896ee.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ce44de...@syzkaller.appspotmail.com

BUG: KASAN: slab-out-of-bounds in firmware_param_path_get+0x348/0x350 drivers/base/firmware_loader/main.c:531
Write of size 1 at addr ffff88810b08ffff by task syz-executor118/303

CPU: 0 PID: 303 Comm: syz-executor118 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
<TASK>
__dump_stack+0x21/0x30 lib/dump_stack.c:88
dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:427 [inline]
kasan_report+0x10f/0x150 mm/kasan/report.c:444
__asan_report_store1_noabort+0x17/0x20 mm/kasan/report_generic.c:311
firmware_param_path_get+0x348/0x350 drivers/base/firmware_loader/main.c:531
param_attr_show+0x150/0x1b0 kernel/params.c:567
module_attr_show+0x56/0x70 kernel/params.c:886
sysfs_kf_seq_show+0x266/0x3d0 fs/sysfs/file.c:61
kernfs_seq_show+0x119/0x160 fs/kernfs/file.c:168
seq_read_iter+0x472/0xce0 fs/seq_file.c:230
kernfs_fop_read_iter+0x146/0x460 fs/kernfs/file.c:241
call_read_iter include/linux/fs.h:2206 [inline]
new_sync_read fs/read_write.c:404 [inline]
vfs_read+0x6c0/0xc20 fs/read_write.c:485
ksys_read+0x14a/0x260 fs/read_write.c:623
__do_sys_read fs/read_write.c:633 [inline]
__se_sys_read fs/read_write.c:631 [inline]
__x64_sys_read+0x7b/0x90 fs/read_write.c:631
x64_sys_call+0x96d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:1
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f5811ee3c39
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd93c09788 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f5811ee3c39
RDX: 000000000000204e RSI: 0000200000002440 RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 00007ffd93c098b8
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd93c098a8
R13: 0000000000000002 R14: 00007f5811f74ca0 R15: 0000000000000002
</TASK>

Allocated by task 300:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:433 [inline]
____kasan_kmalloc mm/kasan/common.c:512 [inline]
__kasan_kmalloc+0xd4/0x100 mm/kasan/common.c:521
kasan_kmalloc include/linux/kasan.h:227 [inline]
__kmalloc+0x13d/0x2c0 mm/slub.c:4436
kmalloc_array include/linux/slab.h:659 [inline]
kcalloc include/linux/slab.h:688 [inline]
alloc_pipe_info+0x1f7/0x4a0 fs/pipe.c:811
get_pipe_inode fs/pipe.c:885 [inline]
create_pipe_files+0x8d/0x6c0 fs/pipe.c:917
__do_pipe_flags+0x4f/0x200 fs/pipe.c:966
do_pipe2+0xa7/0x190 fs/pipe.c:1014
__do_sys_pipe2 fs/pipe.c:1032 [inline]
__se_sys_pipe2 fs/pipe.c:1030 [inline]
__x64_sys_pipe2+0x5a/0x70 fs/pipe.c:1030
x64_sys_call+0x354/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:294
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff88810b08f800
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 1023 bytes to the right of
1024-byte region [ffff88810b08f800, ffff88810b08fc00)
The buggy address belongs to the page:
page:ffffea00042c2200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10b088
head:ffffea00042c2200 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 ffffea00042bc800 0000000500000005 ffff888100043080
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2000(__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, ts 2277022565, free_ts 0
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2607
prep_new_page+0x1c/0x110 mm/page_alloc.c:2613
get_page_from_freelist+0x2c3a/0x2cd0 mm/page_alloc.c:4487
__alloc_pages+0x1a2/0x460 mm/page_alloc.c:5824
alloc_slab_page mm/slub.c:-1 [inline]
allocate_slab mm/slub.c:1937 [inline]
new_slab+0xa0/0x4d0 mm/slub.c:2000
___slab_alloc+0x3ac/0x840 mm/slub.c:3033
__slab_alloc+0x49/0x90 mm/slub.c:3120
slab_alloc_node mm/slub.c:3211 [inline]
slab_alloc mm/slub.c:3255 [inline]
__kmalloc+0x16a/0x2c0 mm/slub.c:4432
__kmalloc_node include/linux/slab.h:487 [inline]
kmalloc_node include/linux/slab.h:642 [inline]
kzalloc_node include/linux/slab.h:761 [inline]
blk_alloc_flush_queue+0xe3/0x250 block/blk-flush.c:477
blk_mq_alloc_hctx block/blk-mq.c:2879 [inline]
blk_mq_alloc_and_init_hctx block/blk-mq.c:3255 [inline]
blk_mq_realloc_hw_ctxs+0xadc/0x1660 block/blk-mq.c:3307
blk_mq_init_allocated_queue+0x3ea/0x1770 block/blk-mq.c:3368
blk_mq_init_queue_data block/blk-mq.c:3203 [inline]
blk_mq_init_queue+0x6c/0xd0 block/blk-mq.c:3213
scsi_alloc_sdev+0x66c/0x9c0 drivers/scsi/scsi_scan.c:319
scsi_probe_and_add_lun+0x180/0x35d0 drivers/scsi/scsi_scan.c:1156
__scsi_scan_target+0x1d2/0xb70 drivers/scsi/scsi_scan.c:1637
scsi_scan_channel drivers/scsi/scsi_scan.c:1725 [inline]
scsi_scan_host_selected+0x34e/0x600 drivers/scsi/scsi_scan.c:1754
page_owner free stack trace missing

Memory state around the buggy address:
ffff88810b08fe80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88810b08ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88810b08ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff88810b090000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88810b090080: 00 00


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